1. Study hard ;) 
This sounds silly, but trust me, if you have a strong desire and 30 days, this will help you a lot!
2. listen to positive affirmations
when you have less time for preparing, you generally lose that confidence. To muster up confidence, listen to something motivational. 
3. Prioritise 
When you prioritize what you have to study first and what next, you become much more systematic.
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Study hard with full determination and try to understand concepts while studying